This application relates to endless belt conveyors of the type in which the upper and lower flight of an endless belt extend around and between a front end drive roller and a rear end return roller. Such types of endless belt conveyors are used to convey material from one point of an industrial or manufacturing facility to another, sometimes directly, and sometimes by utilizing a plurality of such conveyors in sequence in which material is deposited onto one end (feed end) of a conveyor and delivered to the other or discharge end from whence it is discharged onto another conveyor which may be running in an opposite direction or in the same direction. Such conveyors may be positioned on the floor and easily accessible, or they may be positioned up near the ceiling of such manufacturing or industrial facilities to provide more operating space therebelow. Sometimes such conveyors are used to carry discrete items of large size thereon, in which case the features of the present invention are not as relevant. In other cases, however, such conveyors are used to carry particulate material such as tobacco, fibers, grain, sand, and the like thereon. Endless belt conveyors may includes a flat belt; they may have side walls with slanted selvage strips therealong to provide a trough for the material; or the bed of the conveyor itself and the belt may be curved to provide more of a trough-like effect. It is in conjunction with all of these types of conveyors, which carry particulate material, that the present invention is concerned.
In such conveyors for carrying particulate material, several problems may occur. First, depending upon the particulate material, considerable amounts thereof may be lost during the conveying in various ways. First of all, material may be lost at the transfer point from one conveyor to another by the material either being spilled off the sides at the transfer point, or becoming airborne as would be the case in very small powder-like material, such as fibers, or tobacco. Material is also lost at the discharge end of a conveyor where the belt conveyor bends around the drive roller, and the curve that has been built into the conveyor must return to a flat configuration. At this point, it is difficult to constrain the material within the confines of the belt and it is sometimes lost over the edges of the belt as it progresses around the discharge pulleys or rollers. A significant area where particulate material is lost is across the lateral edges of the upper flight of the belt conveyor if there are no side walls thereon. Generally this can be corrected to some extent by providing side walls. Material is also lost that clings to the belt conveyor as it becomes the lower flight returning beneath the upper flight. Often the material that clings to the belt will become deposited either on the floor beneath the conveyor, or on some type of dust pan therebeneath which must be periodically emptied. Finally, material is also lost as the belt moves around the rear or return end of the conveyor. Here, in cases in which there is a dust pan beneath the lower flight, there will be some type of cleat or wiper attached to the conveyor at spaced points to wipe the pan clean and bring it back around the return end of the conveyor to the upper flight. In such cases at the rear end, material is often lost off the edges of the return bight of the conveyor.
A separate problem which occurs, other than lost material, is the damage caused by particulate material which works its way between the flights of the belt conveyor, between the conveyor and its support pans, or between the conveyor and the return rollers. Such material builds up, becomes deposited in the rollers, and eventually will cause damage unless the conveyor is periodically stopped, torn down by a machinist and either cleaned or repaired. This obviously results in expensive down time and maintenance.